Revista da Sociedade Brasileira de Medicina Tropical
ARTIGO
35(6):585-590, nov-dez, 2002.
The use of protein hydrolysate improves the protein intestinal absorption in undernourished mice infected with Schistosoma mansoni O uso de hidrolisado protéico aumenta a absorção intestinal de proteínas em camundongos desnutridos e infectados com Schistosoma mansoni Eridan M. Coutinho1, Haroldo S. Ferreira2, Monica L. Assunção2, Sandra L. Carvalho1, Sheilla A. Oliveira1 and Andréa A. Francelino2
Abstract Patients residing in endemic areas for schistosomiasis in Brazil are usually undernourished and when they develop the hepatosplenic clinical form of the disease should usually receive hospital care, many of them being in need of nutritional rehabilitation before specific treatment can be undertaken. In the mouse model, investigations carried out in our laboratory detected a reduced aminoacid uptake in undernourished animals which is aggravated by a superimposed infection with Schistosoma mansoni. However, in well-nourished infected mice no dysfunction occurs. In this study, we tried to improve the absorptive intestinal performance of undernourished mice infected with S. mansoni by feeding them with hydrolysed casein instead of whole casein. The values obtained for the coefficient of protein intestinal absorption (cpia) among well-nourished mice were above 90% (either hydrolysed or whole protein). In undernourished infected mice, however, the cpia improved significantly after feeding them with hydrolysed casein, animals reaching values close to those obtained in wellnourished infected mice. Key-words: Undernutrition. Schistosomiasis mansoni. Casein hydrolysate. Intestinal protein absorption.
Resumo Portadores de esquistossomose mansônica no Brasil são quase sempre desnutridos e, ao desenvolverem a forma hepatoesplênica da doença, geralmente necessitam de atenção hospitalar. Sob tais circunstâncias seria interessante uma reabilitação nutricional prévia ou paralela ao tratamento específico. Investigações conduzidas em nossos Laboratórios, utilizando camundongos, detectaram redução da absorção protéica entre animais desnutridos, a qual foi agravada por uma infecção superposta com Schistosoma mansoni. Contudo, em camundongos infectados, porém bem nutridos, tal disfunção não foi observada. Objetivou-se avaliar a absorção intestinal de camundongos desnutridos e infectados pelo S. mansoni, alimentados com caseína hidrolisada em comparação com caseína integral. Os resultados obtidos para o Coeficiente de Absorção Intestinal de Proteínas entre os camundongos bem nutridos foram superiores a 90% (tanto HID como INT). Entre os animais desnutridos, contudo, o aumentou significativamente quando se utilizou o hidrolisado protéico, atingindo valores muito próximos daqueles obtidos pelos camundongos infectados e alimentados com a dieta controle. Palavras-chaves: Desnutrição. Esquistossomose mansônica. Hidrolisado protéico. Absorção intestinal de proteína.
1. Centro de Pesquisas Aggeu Magalhães da Fundação Oswaldo Cruz, Recife, PE. 2. Departamento de Nutrição do Centro de Ciências da Saúde da Universidade Federal de Alagoas, Maceió, AL, Brasil. Financial support: from the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo à Pesquisa do Estado de Alagoas (FAPEAL), Fundação Oswaldo Cruz (FIOCRUZ) and Universidade Federal de Alagoas (UFAL) – Brazil. Address to: Prof. Haroldo S. Ferreira. Av. Des. Almeida Guimarães 37, Pajuçara, 57030-160 Maceió, AL, Brasil. Fax: 55 82-214-1665. e-mail:
[email protected], www.nutricaobasica.cjb.ne Recebido para publicação em 17/7/2001.
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the factors involved in the pathogenesis of schistosomiasis and its course to the hepatosplenic clinical form, the parasite burden is considered to be the most important2. For this reason, the effects of two different cercarial burdens were examined in the present study. Although the occurrence of protein malabsorption was demonstrated in undernourished infected mice4 9, the cause of this dysfunction could not be determined. Enzyme deficiency was probably the main factor responsible. This investigation was designed: 1) to evaluate whether a protein hydrolysate based diet (through its aminoacid component) would be better absorbed than a whole protein diet; and 2) to examine the effects of the intensity of infection upon the ability of malnourished infected mice to digest and absorb either dietetic whole protein or hydrolysed protein.
Patients residing in endemic areas for schistosomiasis are usually undernourished23. Such patients when they develop severe clinical forms of the disease should receive hospital care and many of them are given special diets to improve their nutritional status before specific treatment can be established. Usually some dietetic formulae are given to the patients including those utilized in liver cirrhosis, but none take into consideration the singular liver and intestinal lesions related to schistosomiasis mansoni, in which the anatomical and pathophysiological pictures differ from those seen in other diseases. Previous investigations have detected both protein and lipid malabsorption in undernutrition12 14 15 22 25 and schistosomiasis4 7 8 9 10 11 18 19 20. According to investigations by this laboratory4 9, protein malabsorption occurs in undernourished mice and is aggravated when there is a superimposed infection with S. mansoni. However, well nourished infected mice fed control diets have no dysfunction. Of
MATERIAL AND METHODS Animals. Male Swiss weaning (21 to 25 days old) albino mice, weighing 10 to 15g were kept in individual cages under standardized conditions of light and temperature. Infection. Infection was made by the percutaneous route with cercariae of the SL Brazilian strain of Schistosoma mansoni recently shed from Biomphalaria glabrata raised in our laboratory. Diets. A control diet (CONT) was prepared to supply all the nutritional needs of mice21, containing 22.6% protein (Table 1). The experimental diet (EXP) had a low protein content (5.2%) and all the components of the control diet, starch replacing the removed protein. For the absorption tests, diets Test 1 and Test 2 were
prepared, the composition of which was the same as diets CONT and EXP, respectively, except for the substitution of whole casein by hydrolysed casein (N-ZCase Plus, Sigma N4642). Diets were prepared in pellet form. Experimental groups. A batch of 221 mice was initially formed. Only 152 animals survived until the end of the investigation due to spontaneous mortality induced by schistosomiasis infection and/or undernutrition. They were distributed into six groups, according to the type of the ingested diet (CONT or EXP) and to the cercarial burden (mice free of infection, infected with 40 cercariae, infected with 80 cercariae) as shown in Table 2.
Table 1 - Composition of the control diet (proteins, carboidrates, fat and vitamins water solubre and fat solubre). Percentage composition Ingredients
g%
prot
carb
fat
min
water soluble vits
fat soluble vits
fiber
Casein
27.1
22.0
-
-
-
-
-
-
Corn starch
57.4
0.6
50.4
0.1
0.1
-
-
-
Soybean oil
7.5
-
-
7.5
-
-
-
-
Mineral mixture1
4.0
-
-
-
4.0
-
-
-
Water soluble vits2
1.0
-
-
-
-
1,0
-
-
Fat soluble vits3
1.0
-
-
1.0
-
-
1.0
-
Cellulose
2.0
-
-
-
-
-
-
2.0
100.0
22.6
50.4
8.6
4.1
1.0
1.0
2.0
Total
1. Mineral mixture. CaCO3: 600g; K2HPO 4: 645g; CaHPO4.2 H20: 150g; NaCl: 335g; MgSO4. 7H20: 204g; citrate Fe: 20g; MnSO4 : 10g; ZnCl2: 1.5g; CuSO 4: 1.0g; KI: 0.2g; CoC12 : 0.05g; KAl (SO4)2 :0.1g; Na2SeO3 : 0.01g; NaF: 0.2g. 2. Water soluble vitamins: choline HCI: 10g; para-aminobenzoic acid: 5g; inositol: 1g; nicotinic acid: 0.5g; calcium pantothenate: 0.25g; riboflavine: 0.25g; thiamine HCI: 0.20g; pyridoxine HCI: 0.05g; folic acid: 0.05g; biotin: 0.01g, vitamin B12: 0.0005g; corn starch: q.s.p. 300g. 3. Fat soluble vitamins: retinol: 45,000mg; vitamin D2: 750mg; dl-alpha-tocopherol: 5,000mg; vitamin K: 5 mg; corn starch: q.s.p 100g.
Soon after weaning, three groups were fed with CONT diet and three others were offered EXP diet. Diets CONT and EXP were used throughout the investigation except for the last five days of the trial, when the CONT diet was replaced by Test 1 diet. Test 2 diet followed the use of the EXP diet for the respective group of mice.
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Food and water were given ad libitum: after adaptation for a period of three days, subgroups of at least 10 mice on each diet were: a) infected with 40 or b) 80 cercariae of S. mansoni, and a third subgroup was kept free of infection. All the animals were weighed on a weekly basis.
Revista da Sociedade Brasileira de Medicina Tropical 35:585-590, nov-dez, 2002
Table 2 - Mortality rates in undernourished and well-fed mice, regarding Schistosoma mansoni infection and cercarial burden. Mice (no) at the beginning of
spontaneous
sacrificed at the end
the experiment
mortality
of the experiment
(%)
Prot 22.6% (non-infected)
28
2
26
7.1a
Prot 22.6% (40 cercariae)
54
19
35
35.2b
Prot 22.6% (80 cercariae)
40
17
23
42.5b
Prot 5.2% (non-infected)
33
3
30
9.1a
Prot 5.2% (40 cercariae)
24
9
15
37.5b
Prot 5.2% (80 cercariae)
42
19
23
45.2b
Total
221
69
152
31.2
Experimental groups
mortality rates
a; b indicate significant differences (p
